01-30-2017, 12:59 PM
So...I have a Philco 40-195 that I restored...it's been playing fine till today. When turned on it popped and hissed for a while then went quiet except for a quiet hiss from the speaker.
I broke it down and took to the bench. Via some poking around with a nonconductive probe I touched a resistor or two then HEY PRESTO it started playing....except a power down and power up went back to "dead".
Eventually I narrowed it down to the speaker transformer. I unbolted it and moved it a bit and there was a little sparking and noise then it played again. Until once a again I did an off/on...nothing.
Ultimately I found that if I unbolt it and insulate it from the chassis with some cardboard it plays fine. Any contact between the transformer housing and the chassis causes some (slight) sparking then the radio goes dead. Slide the cardboard back in and it plays.
Is there some sort of short inside the transformer grounding it out? Or is there some other possible cause?
I broke it down and took to the bench. Via some poking around with a nonconductive probe I touched a resistor or two then HEY PRESTO it started playing....except a power down and power up went back to "dead".
Eventually I narrowed it down to the speaker transformer. I unbolted it and moved it a bit and there was a little sparking and noise then it played again. Until once a again I did an off/on...nothing.
Ultimately I found that if I unbolt it and insulate it from the chassis with some cardboard it plays fine. Any contact between the transformer housing and the chassis causes some (slight) sparking then the radio goes dead. Slide the cardboard back in and it plays.
Is there some sort of short inside the transformer grounding it out? Or is there some other possible cause?
